The spectrum of double-outlet right atrium including hearts with three atrioventricular
valves.

Abstract

Double-outlet right atrium (DORA) is characterized by simultaneous right atrial emptying
into both ventricles. Ventriculoatrial septal malalignment is the cardinal morphological
feature. Three cases are presented to depict two major types of DORA-DORA with a malaligned
atrial septum and DORA with a malaligned ventricular septum. We describe two subtypes
of each form of DORA: DORA with a malaligned atrial septum presents with either a
common atrioventricular (AV) junction (guarded by a common AV valve) or with a single
AV junction (due to the absence of the left AV junction). DORA with a malaligned ventricular
septum may be associated with a right ventricle (RV) that is adequate for biventricular
repair or a severely hypoplastic RV not compatible with biventricular repair. DORA
with a malaligned ventricular septum is closely related to typical straddling of the
tricuspid valve. Peculiarly, DORA with a malaligned ventricular septum presents three
AV valves at the AV junction and is associated with an abnormal disposition of the
AV conduction axis. Clear understanding of the morphology of these lesions is important
in preventing a surgical misadventure at the crux of the heart.